제주도 성산고등학교, 경험하는 학교

최재성 (주)베토 2025 월간 현대해양 Vol.2025 No.12

평면곡선부 확폭량 재설정에 관한 연구

최재성,백종대 대한교통학회 2000 대한교통학회지 Vol.18 No.4

The objective of this study was to reevaluate current Korean design values for lane width widenings on horizontal currie sections and to develop a new method for derivation of design values based on low-speed offtracking. For this purpose, earlier research were reviewed and necessary equations were derived. Also, the method for derivation of widening values of Korea was compared with that for other countries. The result showed that present Korean method could not consider the variation of lane widths and design speeds of roads. In this Paper, to solve such problems, the new concept of widening was developed. That is the current concept of widening which concerns only the dimension of vehicles and radius of curves was replaced by a new concept that lane width widenings on horizontal curve sections is the difference between the width required on curries and tangents. The width required on a curve consists of the swept Path of a vehicle, lateral clearance, and additional allowance. The width of a tangent is calculated by multiplying lane width by the number of lanes The result of applying new concept shows that the values derived from new concept are higher than current design values for curries have same radius. This study was based only on low-speed offtracking. Therefor, it is recommended that further studies which consider the superelevation and high-speed effect on offtracking be made to derive more accurate widening values .

도시고속도로 엇갈림 구간의 합리적 설계를 위한 교통 특성 분석 (I)

최재성,이승준 대한교통학회 2000 대한교통학회지 Vol.18 No.5

This Paper is a Part of research Project series to analyze unique traffic characteristics observable within weaving sections on urban freeways. The research objectives were to establish with headway distribution and maximum Passing volume on weaving sections the basis of weaving designs that can promote safety and efficiency. Until now, when one wants to check the maximum Passing volume on weaving sections, it is taken for granted using headway distribution of freeway basic section. However. it was suspected in this research that for weaving sections different form of headway distribution had better be used. To prove this, field surveys were made to count headway intervals which supposedly were influenced not only by freeway basic section flows but also by weaving flows and later on used to develop headway distribution for weaving sections. For validation of the developed headway distribution, $x^2$-test was applied to three different data set of observed headways, currently used headway distribution for basic sections(Pearson Type III distribution) and new headway distribution. The result indicated new headway distribution as the most appropriate distribution form. Also, maximum passing volume within weaving sections was calculated based on new headway distribution and compared with Drew's maximum Passing volume.

도로 평면곡선부에서 동적궤도이탈모형 개발에 관한 연구 (굴절차량을 중심으로)

최재성,김우현 대한교통학회 2002 대한교통학회지 Vol.20 No.3

푸르른 영광보리 들녘을 향한 제언

최재성 한국맥류산업발전연구원 2010 한국맥류연구회지 Vol.16 No.-

도로선형에 대한 설계일관성 평가모형의 개발

최재성 대한교통학회 1998 대한교통학회지 Vol.16 No.4

본 연구는 새로운 설계일관성 검토기법의 정립을 위하여 수행되었으며, 이를 위해 속도추정 모형을 개발하였다. 본 연구를 통해 개발된 모형은 차량의 주행속도에 가장 큰 영향을 미치는 주 요소를 고려한 장점을 지니고 있다. 즉 평면곡선에서는 운전자의 시각적 판단을 기초로 등판차량의 주행속도를 추정하였다. 또한 이러한 속도추정이 승용차뿐만 아니라 트럭의 경우로 나누어 이루어짐으로써, 차종별 고려가 가능하도록 하였다. 다음은 본 연구를 통해 이루어진 결과이다. 평면곡선에서는 승용차와 트럭의 속도가 같게 추정되었으며, 시거를 통해 산정된 추정속도는 곡선반경과 밀접한 관계를 갖는다. 종단선형에서 승용차의 속도는 구배의 영향을 받지 않으나, 트럭은 구배의 영향으로 속도가 감소한다. 이 때 트럭에 작용되는 가속도는 모두 세 종류로써, 첫째, crawl speed에 도달할 때까지 작용한 가속도$(a_1)$와 둘째, crawl speed 이후 작용한 가속도$(a_2)$ 그리고 셋째, 하향구배 주행시 작용된 가속도$(a_3)$로 구분된다. Watanatade가 제시한 것과 같이 평지에서 나타나는 평면곡선의 주행속도와 구배지에서의 속도를 단순 비교 함으로써, 작은 속도의 궤적을 따라 평지에서 나타나는 평면곡선의 주행속도와 구배지에서의 속도를 단순 비교함으로써, 작은 속도의 궤적을 따라 합성선형의 속도를 추정하는 것은 합성선형이 차량의 주행속도에 미치는 영향을 간과한 것으로 판단할 수 있다. 그러나 본 모형에서는 합성선형의 영향을 고려하여 승용차와 트럭의 주행속도를 추정함으로써, 보다 현실적으로 주행속도를 추정하였다. 본 연구의 결과는 도로의 설계일관성을 검토하는데 매우 유용한 도구가 될 것이며 향후 운전자의 희망속도 결정, 감속율의 산정, 교통류의 고려, 도로설계의 전산화 자료와 연결 등을 통해 보다 실용적인 결과를 산출할 수 있을 것이다.

The Effect of Post-Treatment N-Acetylcysteine in LPS-Induced Acute Lung Injury of Rats

최재성,이호성,서기현,나주옥,김용훈,어수택,박춘식,오미혜,이상한,김영통 대한결핵및호흡기학회 2012 Tuberculosis and Respiratory Diseases Vol.73 No.1

Background: Oxidation plays an important role in acute lung injury. This study was conducted in order to elucidate the effect of repetitive post-treatment of N-acetylcysteine (NAC) in lipopolysaccaride (LPS)-induced acute lung injury (ALI) of rats. Methods: Six-week-old male Sprague-Dawley rats were divided into 4 groups. LPS (Escherichia coli 5 mg/kg) was administered intravenously via the tail vein. NAC (20 mg/kg) was injected intraperitoneally 3, 6, and 12 hours after LPS injection. Broncho-alveolar lavage fluid (BALF) and lung tissues were obtained to evaluate the ALI at 24 hours after LPS injection. The concentration of tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β)were measured in BALF. Nuclear factor κB (NF-κB), lipid peroxidation (LPO), and myeloperoxidase (MPO) were measured using lung tissues. Micro-computed tomography (micro-CT) images were examined in each group at 72 hours apart from the main experiments in order to observe the delayed effects of NAC. Results: TNF-α and IL-1β concentration in BALF were not different between LPS and NAC treatment groups. The concentration of LPO in NAC treatment group was significantly lower than that of LPS group (5.5±2.8 nmol/mL vs. 16.5±1.6 nmol/mL) (p=0.001). The activity of MPO in NAC treatment group was significantly lower than that of LPS group (6.4±1.8 unit/g vs. 11.2±6.3 unit/g, tissue) (p<0.048). The concentration of NF-κB in NAC treatment group was significantly lower than that of LPS group (0.3±0.1 ng/μL vs. 0.4±0.2 ng/μL) (p=0.0001). Micro-CT showed less extent of lung injury in NAC treatment than LPS group. Conclusion: After induction of ALI with lipopolysaccharide, the therapeutic administration of NAC partially attenuated the extent of ALI through the inhibition of NF-κB activation.

줄어드는 보리, 우리가 지켜야…

최재성 한국맥류산업발전연구원 2010 한국맥류연구회지 Vol.16 No.-

고속도로 합류부 임계차두간격 및 용량 산정에 관한 연구

최재성,이승준 대한교통학회 2001 대한교통학회지 Vol.19 No.6

The objective of the paper is to analyze the traffic characteristics for freeway merging area. Freeway merging area is different from basic section due to ramp vehicles. Therefore, to understand the traffic characteristics of (leeway merging area, this study focused on two factors including critical time headway required in merging maneuver and maximum possible merging volume. In this paper, new model that adopts critical time headway instead of critical time gap in calculating the maximum possible merging volume based on probability function was developed In previous studies, for calculating the maximum possible merging volume, it was considered that merging vehicles could merge freely if a given time gap was greater than the critical time gap. Also, the critical time gap was used as the same value in all traffic flow conditions. But, a time gap required in merging maneuver could be changed, even to the same driver, because difference of relative speed varies in different traffic flow conditions. So, in some cases, the critical time gap could be insufficient value in merging maneuver. Therefore, in this study. a calculating procedure for critical time headway in all traffic flow conditions was presented. Also, the maximum possible merging volume and capacity for freeway merging area were calculated by using the previously found critical time headway.

반복측정의 분할구 자료에 대한 혼합모형

최재성,Choi, Jae-Sung 한국데이터정보과학회 2010 한국데이터정보과학회지 Vol.21 No.1

This paper suggests a mixed-effects model for analyzing split-plot data when there is a repeated measures factor that affects on the response variable. Covariance structures are discussed among the observations because of the assumption of a repeated measures factor as one of explanatory variables. As a plausible covariance structure, compound symmetric covariance structure is assumed for analyzing data. The restricted maximum likelihood (REML)method is used for estimating fixed effects in the model.